Inhaled anesthetics are the agents most used for general anesthesia, mainly due to fast action, ease of administration and monitoring and relative reduced cost, the administration route of the anesthetic consisting of the respiratory device and accomplished by means of gases or powerful volatile liquids, such as the halogen derivative of alkane called fluothane and the halogen derivatives of ether, especially enflurane, as well as malodorous isoflurane, even, more volatile and equally malodorous desflurane, among others.
Recently, evidence of reduced mortality according to the use of volatile agents during heart surgery has led to an increase in the use of inhaled anesthetics.
The process of vaporization of the anesthetic agent in the cardiopulmonary bypass (CPB) is accomplished through a calibrated vaporizer connected to the circuit after the mixer responsible for outputting fresh gases—oxygen and compressed air, where the flow of fresh gases enters the vaporizer and, as the desired concentration is adjusted, the inhaled anesthetic is mixed with the flow of fresh gas, it being vaporized in the circuit up to the membrane oxygenator.
Currently, anesthesia devices comprise components like gas conduction system, vaporizer(s), fan, antipollution system and different monitors that evaluate the physiological function of the anesthetized individual. This integration simultaneously allows monitoring the flow of inhaled and exhaled gases, pressures, volumes and respiratory capacities with compensation of possible losses, besides the current, voltage and amperage of the electric power.
It happens that, even with all safety in the use of inhaled anesthetics, anesthesia devices can develop defects that lead to releasing a percentage of inhaled anesthetics into the atmosphere, initiating pollution in the operating room that promotes contamination of the medical and paramedical team, as well as promoting pollution of the environment. Moreover, the antipollution systems currently used for inhaled anesthetics during cardiopulmonary bypass constitute exhaust systems connected to the membrane oxygenator that, besides causing a negative pressure that can damage the oxygenator membrane, can also cause pollution of the environment, since these gases are eliminated into the atmosphere.
Anesthetic gases like isoflurane, desflurane and sevoflurane are “greenhouse gases,” that is, very aggressive, with a ton of desflurane, for example, being equivalent to the pollution of 3766 tons of carbon dioxide.
To remove anesthetic gases, documents referring to filters or means of retention of inhaled halogenated anesthetic gases were found in the prior art, such as document No. BRMU8601834, which deals with an air filter applied to the expiratory valve in an anesthesia device, for which the air flow expelled by the anesthetized patient is deviated, having the objective of retaining traces of the substances administered, mainly the anesthetic agent, transforming this contaminated air into pure and unpolluted air, which does not attack the environment and does not cause illness to the people present, said filtering element being connected to the output valve of the anesthesia device or in the fan module of the same.
Document No. PI 0509640-5 deals with a system and method for removal of carbon dioxide and carbon monoxide from gas exhaled by the patient during anesthesia. The exhaled gases are dried using nonreactive desiccant to remove water, passed through a filter capable to remove particles bigger than 0.3 microns, passed through a bed comprising natural or synthetic molecular sieves capable of removing carbon dioxide and carbon monoxide and then retaken into the respiratory circuit for recirculation to the patient.
Document No. PI 0511674-0 deals with a detector that monitors the presence of halogenated agents and the presence of N20 and includes a base to which a filter canister is removably connected. The canister has an input to accept exhalant from a patient or an anesthesia machine and an output to send the filtered exhalant as gases to the base. The filtered gases are sent to a gas measurement and monitoring cell lodged in the base. The cell has a system for sensing halogenated agents and a system for sensing N20. When the filter material in the filter canister can no longer filter halogenated agents, the agents are passed from the filter to the measurement cell, which will detect the presence of the halogenated agents. An audible alarm sounds when halogenated agents are detected. This shows the user that it is time to replace the filter canister. If N20 is used, its presence is detected by the N20 sensor in the measurement cell. If N20 is detected, an audible alarm sounds to inform the user that N20 is present and that the user must carry through appropriate preventive steps.
Document No. US2003185735 refers to a process and a device for treatment of a residual anesthetic gas containing a volatile anesthetic and nitrous oxide discharged from an operating room through introduction of the gas into a adsorption cylinder with an adsorbent, where the volatile anesthetic contained in the residual anesthetic gas is adsorbed and in this way removed, and successively introducing the gas inside a catalyst layer filled with a nitrous oxide decomposition catalyst, where the nitrous oxide is decomposed into oxygen and nitrogen. Using the process and the device for treatment of residues of an anesthetic gas of the present invention, a volatile anesthetic having a possibility of destroying the ozone layer or of nitrous oxide as a global warming gas can become harmless, preventing release into the atmosphere.
The documents cited in the paragraphs above, although pertaining to the same field of application, that is, means of filtering anesthetic gases, do not present any of the characteristics of the now improved object, thus guaranteeing that the same meets the legal requirements of patentability.